Fix subpixel precision for line geometry generation

Line geometry generation for rasterization tests wasn't taking the HW
subPixelPrecisionBits limit into account. Modified the triangle creation
routines to round those coordinates down to the driver provided
precision.

Affects:

dEQP-VK.rasterization.*line*
dEQP-GLES*.functional.rasterization.*line*

Components: Framework

VK-GL-CTS issue: 1274

Change-Id: I54af2f9606372bead2a8c7238588374101f80e55

diff --git a/framework/common/tcuRasterizationVerifier.cpp b/framework/common/tcuRasterizationVerifier.cpp
index dd8ff86..12de7e8 100644 (file)
--- a/framework/common/tcuRasterizationVerifier.cpp
+++ b/framework/common/tcuRasterizationVerifier.cpp
@@ -936,15 +936,21 @@ bool verifyMultisampleLineGroupRasterization (const tcu::Surface& surface, const
                        (lineNormalizedDeviceSpace[1] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * viewportSize,
                };
 
-               const tcu::Vec2 lineDir                 = tcu::normalize(lineScreenSpace[1] - lineScreenSpace[0]);
+               const tcu::Vec2 lineScreenSpaceRounded[2] =
+               {
+                       tcu::Vec2(deFloatRound(lineScreenSpace[0].x() * (float)(1 << args.subpixelBits)) / (float)(1 << args.subpixelBits), deFloatRound(lineScreenSpace[0].y() * (float)(1 << args.subpixelBits)) / (float)(1 << args.subpixelBits)),
+                       tcu::Vec2(deFloatRound(lineScreenSpace[1].x() * (float)(1 << args.subpixelBits)) / (float)(1 << args.subpixelBits), deFloatRound(lineScreenSpace[1].y() * (float)(1 << args.subpixelBits)) / (float)(1 << args.subpixelBits))
+               };
+
+               const tcu::Vec2 lineDir                 = tcu::normalize(lineScreenSpaceRounded[1] - lineScreenSpaceRounded[0]);
                const tcu::Vec2 lineNormalDir   = tcu::Vec2(lineDir.y(), -lineDir.x());
 
                const tcu::Vec2 lineQuadScreenSpace[4] =
                {
-                       lineScreenSpace[0] + lineNormalDir * halfLineWidth,
-                       lineScreenSpace[0] - lineNormalDir * halfLineWidth,
-                       lineScreenSpace[1] - lineNormalDir * halfLineWidth,
-                       lineScreenSpace[1] + lineNormalDir * halfLineWidth,
+                       lineScreenSpaceRounded[0] + lineNormalDir * halfLineWidth,
+                       lineScreenSpaceRounded[0] - lineNormalDir * halfLineWidth,
+                       lineScreenSpaceRounded[1] - lineNormalDir * halfLineWidth,
+                       lineScreenSpaceRounded[1] + lineNormalDir * halfLineWidth,
                };
                const tcu::Vec2 lineQuadNormalizedDeviceSpace[4] =
                {
@@ -989,15 +995,21 @@ bool verifyMultisampleLineGroupInterpolation (const tcu::Surface& surface, const
                        (lineNormalizedDeviceSpace[1] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * viewportSize,
                };
 
-               const tcu::Vec2 lineDir                 = tcu::normalize(lineScreenSpace[1] - lineScreenSpace[0]);
+               const tcu::Vec2 lineScreenSpaceRounded[2] =
+               {
+                       tcu::Vec2(deFloatRound(lineScreenSpace[0].x() * (float)(1 << args.subpixelBits)) / (float)(1 << args.subpixelBits), deFloatRound(lineScreenSpace[0].y() * (float)(1 << args.subpixelBits)) / (float)(1 << args.subpixelBits)),
+                       tcu::Vec2(deFloatRound(lineScreenSpace[1].x() * (float)(1 << args.subpixelBits)) / (float)(1 << args.subpixelBits), deFloatRound(lineScreenSpace[1].y() * (float)(1 << args.subpixelBits)) / (float)(1 << args.subpixelBits))
+               };
+
+               const tcu::Vec2 lineDir                 = tcu::normalize(lineScreenSpaceRounded[1] - lineScreenSpaceRounded[0]);
                const tcu::Vec2 lineNormalDir   = tcu::Vec2(lineDir.y(), -lineDir.x());
 
                const tcu::Vec2 lineQuadScreenSpace[4] =
                {
-                       lineScreenSpace[0] + lineNormalDir * halfLineWidth,
-                       lineScreenSpace[0] - lineNormalDir * halfLineWidth,
-                       lineScreenSpace[1] - lineNormalDir * halfLineWidth,
-                       lineScreenSpace[1] + lineNormalDir * halfLineWidth,
+                       lineScreenSpaceRounded[0] + lineNormalDir * halfLineWidth,
+                       lineScreenSpaceRounded[0] - lineNormalDir * halfLineWidth,
+                       lineScreenSpaceRounded[1] - lineNormalDir * halfLineWidth,
+                       lineScreenSpaceRounded[1] + lineNormalDir * halfLineWidth,
                };
                const tcu::Vec2 lineQuadNormalizedDeviceSpace[4] =
                {